If you check or gate-check your Carry-On, you are required to remove the battery and bring it into the cabin with you (where you can keep using it to charge your devices).
If you're flying out of Asia: We recommend removing the battery before you go through security in Asia—they have different airport security regulations, so this will make your trip a little smoother. You can replace it once you're through.
If you're carrying on a Delta or United Airlines flight
If you are carrying onto a Delta or United Airlines flight, the gate agent may ask you to demonstrate that the battery is removable. You can easily remove the battery from our Carry-Ons and bring it into the cabin with you (where you can keep using it to charge your devices).